The effect of surface treatment on the Knoop hardness of Dicor
Naylor, W.P.; Munoz, C.A.; Goodacre, C.J.; Swartz, M.L.; Moore, B.K.
International Journal of Prosthodontics 4(2): 147-151
1991
ISSN/ISBN: 0893-2174 PMID: 1781876 Document Number: 370370
One advantage cited for the use of Dicor over other ceramic materials is a reported Knoop hardness comparable to human enamel. However, when fabricating dental restorations, a Dicor glass-ceramic casting generally is subjected to several different surface treatments because of processing, esthetic, and functional requirements. Therefore, this study compared the Knoop hardness of Dicor specimens under three conditions: (1) cerammed, (2) cerammed and shaded, and (3) sectioned to reveal internal material. Knoop hardness differences between groups were significant (P less than or equal to .05). The cerammed surface was the hardest; it was harder than human enamel. Shaded specimens had a surface hardness comparable to dental porcelain. However, the internal glass-ceramic material, located beneath the shading porcelain and cerammed surface, had a Knoop hardness slightly higher than that of human enamel.